qemu: ensure FDs passed to QEMU for chardevs have correct SELinux labels

The UNIX socket FDs were we passing to QEMU inherited a label based on
libvirtd's context. QEMU is thus denied ability to access the UNIX
socket. We need to use the security manager to change our current
context temporarily when creating the UNIX socket FD.
Reviewed-by: NLaine Stump <laine@laine.org>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

src/qemu/qemu_command.c

@@ -4931,6 +4931,7 @@ qemuOpenChrChardevUNIXSocket(const virDomainChrSourceDef *dev)
  * host side of the character device */
 static char *
 qemuBuildChrChardevStr(virLogManagerPtr logManager,
+                       virSecurityManagerPtr secManager,
                        virCommandPtr cmd,
                        virQEMUDriverConfigPtr cfg,
                        const virDomainDef *def,
@@ -5065,7 +5066,13 @@ qemuBuildChrChardevStr(virLogManagerPtr logManager,
 
     case VIR_DOMAIN_CHR_TYPE_UNIX:
         if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_CHARDEV_FD_PASS)) {
+            if (qemuSecuritySetSocketLabel(secManager, (virDomainDefPtr)def) < 0)
+                goto cleanup;
             int fd = qemuOpenChrChardevUNIXSocket(dev);
+            if (qemuSecurityClearSocketLabel(secManager, (virDomainDefPtr)def) < 0) {
+                VIR_FORCE_CLOSE(fd);
+                goto cleanup;
+            }
             if (fd < 0)
                 goto cleanup;
 
@@ -5404,6 +5411,7 @@ qemuBuildHostdevCommandLine(virCommandPtr cmd,
 
 static int
 qemuBuildMonitorCommandLine(virLogManagerPtr logManager,
+                            virSecurityManagerPtr secManager,
                             virCommandPtr cmd,
                             virQEMUDriverConfigPtr cfg,
                             virDomainDefPtr def,
@@ -5414,7 +5422,8 @@ qemuBuildMonitorCommandLine(virLogManagerPtr logManager,
     if (!priv->monConfig)
         return 0;
 
-    if (!(chrdev = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+    if (!(chrdev = qemuBuildChrChardevStr(logManager, secManager,
+                                          cmd, cfg, def,
                                           priv->monConfig, "monitor",
                                           priv->qemuCaps, true,
                                           priv->chardevStdioLogd)))
@@ -5533,6 +5542,7 @@ qemuBuildSclpDevStr(virDomainChrDefPtr dev)
 
 static int
 qemuBuildRNGBackendChrdevStr(virLogManagerPtr logManager,
+                             virSecurityManagerPtr secManager,
                              virCommandPtr cmd,
                              virQEMUDriverConfigPtr cfg,
                              const virDomainDef *def,
@@ -5550,7 +5560,8 @@ qemuBuildRNGBackendChrdevStr(virLogManagerPtr logManager,
         return 0;
 
     case VIR_DOMAIN_RNG_BACKEND_EGD:
-        if (!(*chr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+        if (!(*chr = qemuBuildChrChardevStr(logManager, secManager,
+                                            cmd, cfg, def,
                                             rng->source.chardev,
                                             rng->info.alias, qemuCaps, true,
                                             chardevStdioLogd)))
@@ -5680,6 +5691,7 @@ qemuBuildRNGDevStr(const virDomainDef *def,
 
 static int
 qemuBuildRNGCommandLine(virLogManagerPtr logManager,
+                        virSecurityManagerPtr secManager,
                         virCommandPtr cmd,
                         virQEMUDriverConfigPtr cfg,
                         const virDomainDef *def,
@@ -5702,7 +5714,7 @@ qemuBuildRNGCommandLine(virLogManagerPtr logManager,
         }
 
         /* possibly add character device for backend */
-        if (qemuBuildRNGBackendChrdevStr(logManager, cmd, cfg, def,
+        if (qemuBuildRNGBackendChrdevStr(logManager, secManager, cmd, cfg, def,
                                          rng, qemuCaps, &tmp,
                                          chardevStdioLogd) < 0)
             return -1;
@@ -8135,6 +8147,7 @@ qemuBuildGraphicsCommandLine(virQEMUDriverConfigPtr cfg,
 static int
 qemuBuildVhostuserCommandLine(virQEMUDriverPtr driver,
                               virLogManagerPtr logManager,
+                              virSecurityManagerPtr secManager,
                               virCommandPtr cmd,
                               virDomainDefPtr def,
                               virDomainNetDefPtr net,
@@ -8157,7 +8170,8 @@ qemuBuildVhostuserCommandLine(virQEMUDriverPtr driver,
 
     switch ((virDomainChrType)net->data.vhostuser->type) {
     case VIR_DOMAIN_CHR_TYPE_UNIX:
-        if (!(chardev = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+        if (!(chardev = qemuBuildChrChardevStr(logManager, secManager,
+                                               cmd, cfg, def,
                                                net->data.vhostuser,
                                                net->info.alias, qemuCaps, false,
                                                chardevStdioLogd)))
@@ -8225,6 +8239,7 @@ qemuBuildVhostuserCommandLine(virQEMUDriverPtr driver,
 static int
 qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
                               virLogManagerPtr logManager,
+                              virSecurityManagerPtr secManager,
                               virCommandPtr cmd,
                               virDomainDefPtr def,
                               virDomainNetDefPtr net,
@@ -8356,7 +8371,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
         break;
 
     case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
-        ret = qemuBuildVhostuserCommandLine(driver, logManager, cmd, def,
+        ret = qemuBuildVhostuserCommandLine(driver, logManager, secManager, cmd, def,
                                             net, qemuCaps, bootindex,
                                             chardevStdioLogd);
         goto cleanup;
@@ -8534,6 +8549,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
 static int
 qemuBuildNetCommandLine(virQEMUDriverPtr driver,
                         virLogManagerPtr logManager,
+                        virSecurityManagerPtr secManager,
                         virCommandPtr cmd,
                         virDomainDefPtr def,
                         virQEMUCapsPtr qemuCaps,
@@ -8566,7 +8582,7 @@ qemuBuildNetCommandLine(virQEMUDriverPtr driver,
         for (i = 0; i < def->nnets; i++) {
             virDomainNetDefPtr net = def->nets[i];
 
-            if (qemuBuildInterfaceCommandLine(driver, logManager, cmd, def, net,
+            if (qemuBuildInterfaceCommandLine(driver, logManager, secManager, cmd, def, net,
                                               qemuCaps, bootNet, vmop,
                                               standalone, nnicindexes,
                                               nicindexes,
@@ -8629,6 +8645,7 @@ qemuBuildSmartcardFindCCIDController(const virDomainDef *def,
 
 static int
 qemuBuildSmartcardCommandLine(virLogManagerPtr logManager,
+                              virSecurityManagerPtr secManager,
                               virCommandPtr cmd,
                               virQEMUDriverConfigPtr cfg,
                               const virDomainDef *def,
@@ -8702,7 +8719,8 @@ qemuBuildSmartcardCommandLine(virLogManagerPtr logManager,
             return -1;
         }
 
-        if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+        if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                              cmd, cfg, def,
                                               smartcard->data.passthru,
                                               smartcard->info.alias,
                                               qemuCaps, true,
@@ -8862,6 +8880,7 @@ qemuBuildShmemBackendMemProps(virDomainShmemDefPtr shmem)
 
 static int
 qemuBuildShmemCommandLine(virLogManagerPtr logManager,
+                          virSecurityManagerPtr secManager,
                           virCommandPtr cmd,
                           virQEMUDriverConfigPtr cfg,
                           virDomainDefPtr def,
@@ -8933,7 +8952,8 @@ qemuBuildShmemCommandLine(virLogManagerPtr logManager,
     VIR_FREE(devstr);
 
     if (shmem->server.enabled) {
-        devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+        devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                        cmd, cfg, def,
                                         &shmem->server.chr,
                                         shmem->info.alias, qemuCaps, true,
                                         chardevStdioLogd);
@@ -9020,6 +9040,7 @@ qemuChrIsPlatformDevice(const virDomainDef *def,
 
 static int
 qemuBuildSerialCommandLine(virLogManagerPtr logManager,
+                           virSecurityManagerPtr secManager,
                            virCommandPtr cmd,
                            virQEMUDriverConfigPtr cfg,
                            const virDomainDef *def,
@@ -9043,7 +9064,8 @@ qemuBuildSerialCommandLine(virLogManagerPtr logManager,
         if (serial->source->type == VIR_DOMAIN_CHR_TYPE_SPICEPORT && !havespice)
             continue;
 
-        if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+        if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                              cmd, cfg, def,
                                               serial->source,
                                               serial->info.alias,
                                               qemuCaps, true,
@@ -9080,6 +9102,7 @@ qemuBuildSerialCommandLine(virLogManagerPtr logManager,
 
 static int
 qemuBuildParallelsCommandLine(virLogManagerPtr logManager,
+                              virSecurityManagerPtr secManager,
                               virCommandPtr cmd,
                               virQEMUDriverConfigPtr cfg,
                               const virDomainDef *def,
@@ -9092,7 +9115,8 @@ qemuBuildParallelsCommandLine(virLogManagerPtr logManager,
         virDomainChrDefPtr parallel = def->parallels[i];
         char *devstr;
 
-        if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+        if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                              cmd, cfg, def,
                                               parallel->source,
                                               parallel->info.alias,
                                               qemuCaps, true,
@@ -9113,6 +9137,7 @@ qemuBuildParallelsCommandLine(virLogManagerPtr logManager,
 
 static int
 qemuBuildChannelsCommandLine(virLogManagerPtr logManager,
+                             virSecurityManagerPtr secManager,
                              virCommandPtr cmd,
                              virQEMUDriverConfigPtr cfg,
                              const virDomainDef *def,
@@ -9127,7 +9152,8 @@ qemuBuildChannelsCommandLine(virLogManagerPtr logManager,
 
         switch (channel->targetType) {
         case VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_GUESTFWD:
-            if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+            if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                                  cmd, cfg, def,
                                                   channel->source,
                                                   channel->info.alias,
                                                   qemuCaps, true,
@@ -9144,7 +9170,8 @@ qemuBuildChannelsCommandLine(virLogManagerPtr logManager,
             break;
 
         case VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_VIRTIO:
-            if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+            if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                                  cmd, cfg, def,
                                                   channel->source,
                                                   channel->info.alias,
                                                   qemuCaps, true,
@@ -9166,6 +9193,7 @@ qemuBuildChannelsCommandLine(virLogManagerPtr logManager,
 
 static int
 qemuBuildConsoleCommandLine(virLogManagerPtr logManager,
+                            virSecurityManagerPtr secManager,
                             virCommandPtr cmd,
                             virQEMUDriverConfigPtr cfg,
                             const virDomainDef *def,
@@ -9187,7 +9215,8 @@ qemuBuildConsoleCommandLine(virLogManagerPtr logManager,
                 return -1;
             }
 
-            if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+            if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                                  cmd, cfg, def,
                                                   console->source,
                                                   console->info.alias,
                                                   qemuCaps, true,
@@ -9208,7 +9237,8 @@ qemuBuildConsoleCommandLine(virLogManagerPtr logManager,
                 return -1;
             }
 
-            if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+            if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                                  cmd, cfg, def,
                                                   console->source,
                                                   console->info.alias,
                                                   qemuCaps, true,
@@ -9223,7 +9253,8 @@ qemuBuildConsoleCommandLine(virLogManagerPtr logManager,
             break;
 
         case VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_VIRTIO:
-            if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+            if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                                  cmd, cfg, def,
                                                   console->source,
                                                   console->info.alias,
                                                   qemuCaps, true,
@@ -9342,6 +9373,7 @@ qemuBuildRedirdevDevStr(const virDomainDef *def,
 
 static int
 qemuBuildRedirdevCommandLine(virLogManagerPtr logManager,
+                             virSecurityManagerPtr secManager,
                              virCommandPtr cmd,
                              virQEMUDriverConfigPtr cfg,
                              const virDomainDef *def,
@@ -9354,7 +9386,8 @@ qemuBuildRedirdevCommandLine(virLogManagerPtr logManager,
         virDomainRedirdevDefPtr redirdev = def->redirdevs[i];
         char *devstr;
 
-        if (!(devstr = qemuBuildChrChardevStr(logManager, cmd, cfg, def,
+        if (!(devstr = qemuBuildChrChardevStr(logManager, secManager,
+                                              cmd, cfg, def,
                                               redirdev->source,
                                               redirdev->info.alias,
                                               qemuCaps, true,
@@ -10065,6 +10098,7 @@ qemuBuildVsockCommandLine(virCommandPtr cmd,
 virCommandPtr
 qemuBuildCommandLine(virQEMUDriverPtr driver,
                      virLogManagerPtr logManager,
+                     virSecurityManagerPtr secManager,
                      virDomainObjPtr vm,
                      const char *migrateURI,
                      virDomainSnapshotObjPtr snapshot,
@@ -10181,7 +10215,7 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
     if (qemuBuildSgaCommandLine(cmd, def, qemuCaps) < 0)
         goto error;
 
-    if (qemuBuildMonitorCommandLine(logManager, cmd, cfg, def, priv) < 0)
+    if (qemuBuildMonitorCommandLine(logManager, secManager, cmd, cfg, def, priv) < 0)
         goto error;
 
     if (qemuBuildClockCommandLine(cmd, def, qemuCaps) < 0)
@@ -10211,29 +10245,29 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
     if (qemuBuildFSDevCommandLine(cmd, def, qemuCaps) < 0)
         goto error;
 
-    if (qemuBuildNetCommandLine(driver, logManager, cmd, def,
+    if (qemuBuildNetCommandLine(driver, logManager, secManager, cmd, def,
                                 qemuCaps, vmop, standalone,
                                 nnicindexes, nicindexes, &bootHostdevNet,
                                 chardevStdioLogd) < 0)
         goto error;
 
-    if (qemuBuildSmartcardCommandLine(logManager, cmd, cfg, def, qemuCaps,
+    if (qemuBuildSmartcardCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
                                       chardevStdioLogd) < 0)
         goto error;
 
-    if (qemuBuildSerialCommandLine(logManager, cmd, cfg, def, qemuCaps,
+    if (qemuBuildSerialCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
                                    chardevStdioLogd) < 0)
         goto error;
 
-    if (qemuBuildParallelsCommandLine(logManager, cmd, cfg, def, qemuCaps,
+    if (qemuBuildParallelsCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
                                       chardevStdioLogd) < 0)
         goto error;
 
-    if (qemuBuildChannelsCommandLine(logManager, cmd, cfg, def, qemuCaps,
+    if (qemuBuildChannelsCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
                                      chardevStdioLogd) < 0)
         goto error;
 
-    if (qemuBuildConsoleCommandLine(logManager, cmd, cfg, def, qemuCaps,
+    if (qemuBuildConsoleCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
                                     chardevStdioLogd) < 0)
         goto error;
 
@@ -10258,7 +10292,7 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
     if (qemuBuildWatchdogCommandLine(cmd, def, qemuCaps) < 0)
         goto error;
 
-    if (qemuBuildRedirdevCommandLine(logManager, cmd, cfg, def, qemuCaps,
+    if (qemuBuildRedirdevCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
                                      chardevStdioLogd) < 0)
         goto error;
 
@@ -10271,7 +10305,7 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
     if (qemuBuildMemballoonCommandLine(cmd, def, qemuCaps) < 0)
         goto error;
 
-    if (qemuBuildRNGCommandLine(logManager, cmd, cfg, def, qemuCaps,
+    if (qemuBuildRNGCommandLine(logManager, secManager, cmd, cfg, def, qemuCaps,
                                 chardevStdioLogd) < 0)
         goto error;
 
@@ -10306,7 +10340,7 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
         goto error;
 
     for (i = 0; i < def->nshmems; i++) {
-        if (qemuBuildShmemCommandLine(logManager, cmd, cfg,
+        if (qemuBuildShmemCommandLine(logManager, secManager, cmd, cfg,
                                       def, def->shmems[i], qemuCaps,
                                       chardevStdioLogd))
             goto error;

src/qemu/qemu_command.h

@@ -46,6 +46,7 @@ VIR_ENUM_DECL(qemuVideo)
 
 virCommandPtr qemuBuildCommandLine(virQEMUDriverPtr driver,
                                    virLogManagerPtr logManager,
+                                   virSecurityManagerPtr secManager,
                                    virDomainObjPtr vm,
                                    const char *migrateURI,
                                    virDomainSnapshotObjPtr snapshot,

src/qemu/qemu_process.c

@@ -6174,6 +6174,7 @@ qemuProcessLaunch(virConnectPtr conn,
     VIR_DEBUG("Building emulator command line");
     if (!(cmd = qemuBuildCommandLine(driver,
                                      qemuDomainLogContextGetManager(logCtxt),
+                                     driver->securityManager,
                                      vm,
                                      incoming ? incoming->launchURI : NULL,
                                      snapshot, vmop,
@@ -6642,6 +6643,7 @@ qemuProcessCreatePretendCmd(virQEMUDriverPtr driver,
     VIR_DEBUG("Building emulator command line");
     cmd = qemuBuildCommandLine(driver,
                                NULL,
+                               driver->securityManager,
                                vm,
                                migrateURI,
                                NULL,